There is a current trend for commercially available granular detergent compositions to have higher bulk densities as well as higher active ingredient content. Such detergent compositions offer greater convenience to the consumer and at the same time, reduce the amount of packaging materials which will ultimately be disposed of. But for such granular detergent compositions, there are problems of poor dissolution resulting in residue and/or partially dissolved detergent clump/gel-like mass left on fabric, in the washing machine, or in a washing machine dispenser drawer. This residue can vary from fine particles to masses as large as 10 to 100 millimeters in size, and is very undesirable for consumers.
Although not wanting to be limited by theory, several examples are illustrated showing how poor dissolution may occur. For example, when consumers first put detergent composition and clothes in the washing machine prior to the addition of water in the tub, significant residue is left in the tub or on the clothes. This residue is formed as the machine is filling with water, since the detergent is trapped in the clothes and there is no agitation of the tub contents. Under these conditions, hydration and dissolution occur on the surface of the detergent, wherein the detergent forms a hydrated paste, or gel-like mass.
In another example, detergent compositions containing zeolite-built powders dispense poorly, especially when such compositions are placed in a dispenser drawer of a washing machine and/or a detergent dosing device. This poor dispensing may be caused by the formation of a gel-like mass, which have high levels of surfactant, upon contact with water. The gel-like mass prevents a proportion of the detergent powder from being solubilized in the wash water, which reduces the effectiveness of the detergent. These solubility problems especially occur in conditions having low water pressures and/or lower washing temperatures.
It is known that bleach activators in powder form do not remain stable when incorporated in detergent compositions. Therefore, such particles are used as extrudates or otherwise formed into larger bleach activator particles or bodies in order to maintain the stability of the bleach activator particles. But these large particles have dissolution problems in the wash solution. As a result, water-soluble disintegrants have been used in large bleach activator particles in order to have better dissolution of the bleach activators. In this technique, the water-soluble disintegrants are incorporated into the large bleach activator particle. Then, as moisture is exposed to the large particle, the water-soluble disintegrants solubilize in the wash solution, leaving gaps in the large particle, and thereby promote the rupturing of the large particle and release the activator particles to the water.
It is also known to use disintegrating aids in bleach activator particles that are not very water-soluble, but are water-swellable in the presence of water, such as upon contact with the wash solution. In this technique, larger particles containing these water-swellable disintegrants break up into small particles due to the swelling up of the disintegrants, thus releasing the activator into the wash solution.
It has now been surprisingly found that the use of substantially water-insoluble disintegrants can improve the dissolution of detergent granules containing high levels of surfactant. Particularly, it has been surprisingly found that the water-insoluble disintegrants improve the dissolution of residue and/or partially dissolved detergent clump/gel-like masses.
None of the existing art provides all of the advantages and benefits of the present invention.